Physical illness vs mental illness

Well I have had the flu the last week and a half. I’ve hardly spoken to anyone (well I did lose my voice for awhile there), and generally felt miserable. However I was surprised this didn’t affect my mental health. Mentally I am very healthy. This is confusing to me. Why should I be mentally miserable one week and not the next? No change in medications. No change in circumstances. The nightmares stopped a few days ago, which I’m sure has a lot to do with my mental stability. But why did they stop?

In any case, I am grateful. And, given a choice between physical and mental illness – although they are equally debilitating – I’d choose physical illness any day.